Ok guys messin with the nv4500 some more and noticed that when the 2nd gear shift collar is slid in to 2nd gear it has alot of movement meaning it is easy to move back to the edge of the teeth on the 2nd gear is this normal ive serched for answers or videos and cant find the answer and would like to know before i put the top cover on

Check the main shaft bearings. If the main shaft can move forward to back even a little bit then the main shaft can kick it out of gear. Most normally the detent holds it in place. The usual reason for bouncing out of gear is mainshaft bearing are wore. 

So does the shift fork actually keep it there, its not the bearings heres a little back story its a full rebuild hasnt been finished yet it has new input shaft new main shaft new counter shaft all new bearings including needle bearings new syncros new 1,2 syncro hub all new syncro sliders new syncro struts and springs new thrust washers new reverse gear both main and counter shaft shimmed as close to .002 as possible and a complete new top cover it looks to engage 2nd good with the top on but i was refering to with out the top on by just putting it in 2nd by hand the syncro sleve just barely engagues the gear teeth unless i hold it and wasnt forsure if the fork was suppost to hold it up there or not. I maby over thinking it but really dont want to have to pull it out again

Shift collar detent holds it there. Shift fork just moves it into place of 2nd gear. It up to that detent to hold the shift collar.

When i pull it it clicks in to 2nd but at this point it barely enguages the teeth i even tried the orginal parts and the same result so what could cause this

Bearings on the main shaft are in the wrong position. This would mean that 4th gear should be the same issue being it pushed in the same direction. If not then something on the main shaft is not assembled right or out of order.

BeRings are correct and 2nd is the only one having the issue all others engage perfect i have had this main shaft apart 3 times and followed the nv4500 service manual to a tee i even stacked  the oem shaft to make sure it wasnt the after market shaft  which is why im so confused ive checked all parts 3 times and cant find a issue which is why im asking  i even compared the oem snap rings to the after market and the oem syncros  so im starting to think im over thinking it . The struts on the 1 2 hub are odd to me but its my first 4500  they seem to let the collar still move alot even after they engage  but its the same even with all oem parts or aftermarket if i had a video and could up load it i would

I took lots of pictures  of the last one that I did. Main shaft broke. It looks like the 1-2 shift collar with the wide bevel  goes to the front and the squared up end goes toward the rear.